Thread: Weird errors

Hi, i'm building a application and at a certain point, i get the weirdest runtime errors:

for example:

Code:

		try{
			bufptr += my_strcpy(target->ServerName, bufptr);
			bufptr += my_strcpy(target->MapName, bufptr);
			bufptr += my_strcpy(target->Game, bufptr);
			bufptr += my_strcpy(target->GameType, bufptr);
			bufptr += 2; //Skip appid because it is no use to us
			target->PlayerCount = static_cast<unsigned short>(*bufptr++);
			target->MaxPlayers = static_cast<unsigned short>(*bufptr++);
			bufptr+=3;
		}
		catch (std::bad_alloc&){
			return -1;
		}
		catch(void *){
			return -1;
		}

for some or other reason, the app jumps to the first catch block while executing this line:

Code:

bufptr+=3;

Code:

009936F5  mov         eax,dword ptr [ebp-48h] 
009936F8  add         eax,3 
009936FB  mov         dword ptr [ebp-48h],eax 
009936FE  jmp         $LN19 (99372Ch)

the jump leads straight to the catch block so why is it there :S
Some other strange things are that whether i place some other code at that location. the catch block kicks in at that code.

you might think that with buffer+=3, i have a overflow but thats not. bufptr points to the very beginning of a large large array of chars named buffer.


my_strcpy definition:

Code:

	inline int my_strcpy(char* source, char* target){
		int counter(0);
		while (*target!=0){
			*source++=*target++;
			++counter;
		}
		*source = 0;
		return counter+1;
	}

edit

yet another weird thing. the function wont return with the return -1 cmd in the catch block. it just continues :S

Could you please post your code?
I suppose you just made a very stupid mistake in your code.

Originally Posted by Daved

Why does my_strcpy copy from target to source? Normally it would be the other way around.

Because of this:

Code:

*source++=*target++;

You copy a function from somewhere and you don't even understand it.
And still, you don't want to use the standard ways to do it.

Originally Posted by anon

Are you sure there is anything that might throw an error in my_strcpy (writing to random memory being undefined behaviour)? Other than that, my_strcpy doesn't look very safe. Why make your own if there are better ones available.

thats the thing, i could use standard defined ones but that would be much slower, this is a strlen and strcpy in one and the whole application is based on speed.
Personally, i believe this is a compile bug, because the Assembly is just messed up. Posting the code wont be relevant, because everything is very ok there edit, and the naming.... hence, its ugly but neither that is relevant

Originally Posted by Daved

You misunderstood the question. I know how the function copies from target to source. The question was why does it not copy from source to target. Variable names should show intent, and when the code does the opposite of what the variable names indicate, it is either a mistake or poor design. Perhaps in this case that is the solution to the problem.

Sorry, I didn't notice it was you...

The ESP register is the stack pointer: it points to the top of the stack, ie it contains the address of the top of the stack. Whenever anything is pushed on the stack the ESP register automatically changes.

.....